Engine warning light not working

[mr_pepps]

Hi all,

Took my 1999 A3 1.8T for MoT yesterday.
Failed because MIL light not working.

Any known or common reason why the engine warning light might not come on during ignition/check stage?

The display still shows 'OK' after the ignition checks have completed. But no engine warning light shows.

I read here that disconnecting the battery for 30 mins can reset the ECU.
I shall try that first.

Any other tips gratefully received. Have to get this sorted before 21st Dec.

Thanks,

Julian

 

[<tuffty/>]

Any fault codes?

People have a habit of taping over the eml when selling cars to hide issues... Check for fault codes in the first instance then maybe worth either doing an output test in vcds on the instruments to check if the eml comes on at all or removing the cluster to see if it's been taped over

<tuffty/>

 

[mr_pepps]

I've msg'd member @Gooders to see if they can scan my car. Until then I'll check the cluster.
I had the whole lot out in the summer because my DIS suddenly stopped lighting up. Don't remember anything being taped over.

Julian

 

[Stuart B]

Did you press the button on the stalk which switches the DIS off?

 

[mr_pepps]

Did you press the button on the stalk which switches the DIS off?

A fair shout but no I'm quite familiar with the car - had it for several years now.

The DIS failed after I re-connected the reverse switch cable onto the gearbox. At least that's the only job I remember doing when I noticed the DIS was no longer working. I usually drove with the DIS switched off, or left on blank setting. (Something the 8P model when I had one wouldn't let me do.)

But I can't remember if the engine warning light failed at the same time.

 

[Gooders]

Not had a message have pm you


Sent from my iPhone using Tapatalk

 

[mr_pepps]

Update:
Met with @Gooders who kindly scanned my car.
V strange readings: (pasted from my phone)


Address 17: Instruments Labels: 8L0-920-xxx-17.lbl

Part No: 8L0 920 980 A

Component: AB-KOMBIINSTR. VDO D07

Coding: 00444

Shop #: WSC 00000

VCID: 316EB3A7FBBF84C26A-5178


Component: AUZ7Z0X1156133

ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ AUZ7Z0X1156133


No fault code found.


So no faults but still no EPC light when I turn on the ignition.
Gooders tested the instrument display with vcds, EPC light did light up under test conditions, but doesn't under normal use.

I'll be taking the binnacle out this evening to look for unclipped wires.

If anyone has any further ideas please let me know.

Top man @Gooders for helping out on a very rainy Sunday evening

 

[mr_pepps]

@<tuffty/> @Stuart B
Hello there - do you recognise anything in that diagnostic I posted above? Really hoping to try and find someone with similar experiences so I can get a fix in before Friday.

 

[<tuffty/>]

No fault code is no fault code... means there is no known fault...

You will need to take the cluster out and pull it apart to check if someone has taped over any of the warning lights... they are all LED's and soldered on the board so no bulbs to remove etc...

<tuffty/>

 

[mr_pepps]

@<tuffty/> Hi thanks for getting back to me.
The ECU lamp lit fine when the dashboard illumination test was carried out via VCDS, so there's no tape covering anything up.

Is there any other link you or others might know about regarding a DIS which doesn't display DIS functions and an ECU warning light which doesn't illuminate when its supposed to?

All help hugely appreciated as always.

 

[mr_pepps]

Update:

• reset ECU by method of disconnecting negative batt terminal for 30 mins - no ECU light

• took cluster out and checked for any signs of damage. None found. Reassembled and tested - no ECU light

Still need help if anyone can suggest anything else to try.

Says in the Haynes book that if I disconnect the ECU itself I'll need it re-programmed by Audi. Anyone know if this is true or are there easier and cheaper ways to get the ECU back to form if I remove it?

 

[<tuffty/>]

What engine code is your car?

<tuffty/>

 

[mr_pepps]

Hi,

It's an AGU engine.

 

[<tuffty/>]

Ah. . AGU doesn't have a CEL apparently ..

<tuffty/>

 

[mr_pepps]

What's a CEL please?

 

[mr_pepps]

@<tuffty/> (user name corrected)

CEL Check Engine Light?

Not on an AGU? So it may not be an MoT failure after all?

There is an ECU light though. But are you suggesting that this doesn't come on during start-up, but does only if there's a problem?

 

[<tuffty/>]

Just so we are clear... you are referring to this light...

I don't own an AGU or have much experience of them but the subject of the CEL on an AGU was discussed not so long back (on a similar MOT related thread iirc) and @Prawn who is one of our resident AGU 'experts' said that AGU's don't have one...

By all accounts there isn't even an LED in the cluster to support one...

<tuffty/>

 

[mr_pepps]

Hi @Tufty

Here's a photo from my user manual. It shows there's an EPC light on the tacho (sort of between 1 and 2 thousand rpm).
The text states this is supposed to illuminate on startup, then go off (unless there's a fault).

This is the light I'm talking about. It came on when told to by vcds on a dashboard illuminations test, but it doesn't come on when it should when I start the car.

 

[<tuffty/>]

Pretty sure that would be because you have a cable throttle not drive by wire

EPC is for drive by wire cars as far as I am aware

<tuffty/>

 

[<tuffty/>]

...hummm... maybe showing my lack of AGU knowledge here but... from the description in the screenshot it suggests that the EPC light is the AGU equivalent of the CEL (pictured in my post) for drive by wire cars...

EPC is electronic pedal control in drive by wire world...

As you have no fault codes and assuming that the EPC/CEL should come on then I would still consider taking the cluster apart and check to see if soeone has taped over the EPC light to hide faults for sale of the car

<tuffty/>

 

[mr_pepps]

Hi - thanks.
EPC light illuminates on test with VCDS. So not a tape covering a lamp problem.
The manual states that this light should come on during ingnition, as shown in the pic. That's why the MoT centre won't pass the car, 'cause that light doesn't come on during ignition.

You're right my car isn't fly-by-wire, but that EPC light should surely illuminate during ignition.

I'll keep searching - is there a good Audi group on Facebook that your good self or anyone else can recommend?

Thanks for all your help @<tuffty/> (edited user to correct... don't worry, you'll get it eventually lol)

 

[<tuffty/>]

Just had a read up on the relevant section for the MOT...

I suppose it could be the cluster itself thats faulty but difficult to say really...

Might be worth doing an emissions readiness check in vcds
http://www.ross-tech.com/vcds/tour/readiness.php

...just in case there is a condition the ECU is confused about... also maybe worth physically checking the ECU for any corroded pins.... just been looking at an AGU wiring diagram for the pin number of the EPC/CEL as I know there is one for the later cars... maybe its that connection that is a problem here

<tuffty/>

 

[<tuffty/>]

https://workshop-manuals.com/audi/a...nectors_at_dash_panel_insert_model_year_1997/

I think... its blue plug, pin 13

<tuffty/>

 

[mr_pepps]

Aha ok cool I'll check out the ECU itself tomorrow in the daylight.
Thanks @<tuffty/> (Success!!!!)

One thing that concerns me with this - the Haynes book states if I disconnect the ECU I'll have to get it re-coded by Audi. So will the vehicle be driveable afterwards?

Thanks!

 

[<tuffty/>]

Disconnecting the ECU should be no different to disconnecting the battery... pretty sure you don't need to re-code a car each time you disconnect the battery... well not a 1999 VAG at least

I can't speak for the AGU ECU specifically but I have removed/refitted loads of ECU's from 1.8t cars (including my own) with no issue... I suspect its Haynes covering its a55...

You may need to do a throttle alignment... that would require VCDS so maybe why Haynes suggest 're-coding'
http://wiki.ross-tech.com/wiki/index.php/Throttle_Body_Alignment_(TBA)

<tuffty/>

 

[Stuart B]

Is it possible that vcds can do a lamp test for a multi purpose dashpod, but the ignition knows the car is not fitted with fly by wire so doesn't illuminate EPC ?
There has been umpteen issues specifically with AGU engines regarding MOT failures.

 

[mr_pepps]

@Stuart B @<tuffty/>
Hi both. Thanks for your comments and help.
I've spoken with the 3 local Audi main dealers near me - Maidstone, East Kent and Tonbridge. None were able to speak of any familiarity with this issue.
Maidstone declared every single car on the road has an EPC light or equivalent. I decided not to debate that and moved on.
East Kent ran a check against my VIN while I was on the phone to check for anything outstanding re: software with my car. Then stated a diagnostic session costs £120.
Tonbridge had no experience of this fault and offered a diagnostic for £99.

I've posted a message to the Audi UK Facebook group to see if anyone can help from that angle.

Just need someone from Audi to confirm whether or not my car is supposed to display the EPC light on start-up. If it isn't I'll be able to contest the MoT fail, get a certificate and drive my car again.
If nobody from Audi can tell me if my car is supposed to show an EPC light on start up I might have to change the whole car! This is insane!
I'm determined to find a way around this.

 

[Tj 0785]

Why not take it to a different mot tester

 

[mr_pepps]

@Tj0785 Hello thanks for your idea - it's not a bad one, only that the MoT regulations will be the same. Another tester should fail the car too unless they know for sure if my car should or shouldn't display the EPC light.
Most businesses will be open again tomorrow. I'll get back on the phone and ask some more questions.

 

[Tj 0785]

Mot testers are pot luck some will pass car with decats some won’t, some fail cars on number plate spacing some wouldn’t look twice at it. I’d try that before getting a new car

 

[mr_pepps]

@Tj 0785 I took your advice and phoned a few local garages. Finally spoke with a guys who knows older VAG cars and agrees mine shouldn't display an EPC check.
Said he'll MoT it for me on Thursday.
Fingers crossed.

Anything of interest I'll post here and then hopefully this EPC mystery on a 1999 1.8T A3 will be sorted for anyone else who might find themselves in a similar fix.

 

[<tuffty/>]

I assume forcing a fault like disconnecting the MAF or similar turns the CEL on?

As long as the CEL operates on a fault then it shouldn't be an issue...

<tuffty/>

 

[Gooders]

@Tj 0785 I took your advice and phoned a few local garages. Finally spoke with a guys who knows older VAG cars and agrees mine shouldn't display an EPC check.
Said he'll MoT it for me on Thursday.
Fingers crossed.

Anything of interest I'll post here and then hopefully this EPC mystery on a 1999 1.8T A3 will be sorted for anyone else who might find themselves in a similar fix.

Hope it gets sorted. Be a good bit of gen for the group to know.


Sent from my iPhone using Tapatalk

 

[Prawn]

There is no CEL on an AGU A3. I can promise you this!

No light to come on, at start up or for faults.

The tester in this case is an idiot and has caused you a load of grief for no good reason!

 

[badger5]

There is no CEL on an AGU A3. I can promise you this!

No light to come on, at start up or for faults.

The tester in this case is an idiot and has caused you a load of grief for no good reason!

agreed.

 

[mr_pepps]

SOLVED: Sorry I should have posted this ages ago. Anyay the issue was solved by a different MoT centre who, like @Prawn and @badger5 said, declared there wasn't a MIL or equivalent fitted on my 1999 AGU. He stated that the light in question was brought in to the A3 range from 2003.

Anyway. Cost me money and time. The original MoT centre wouldn't refund my fee. The buggers.
Avoid MOTEST Faversham, ME13 (Kent) unless you're prepared for a fight over what's what.

The tester who saved the day was TOMSETT Kent, Church Farm, Church Ln, Stockbury, Sittingbourne ME9 7RD. Excellent facilities, genuine family firm, no nonsense.